On 10/30/19 6:52 AM, Liu Xiang wrote: > Fix comments of __get_user_pages() and get_user_pages_remote(), > make them more clear. > > Suggested-by: John Hubbard <jhubbard@xxxxxxxxxx> > Signed-off-by: Liu Xiang <liuxiang_1999@xxxxxxx> > > --- > > Changes in v3: > as suggested by John, apply the same fix to get_user_pages_remote(). > --- > mm/gup.c | 32 ++++++++++++++++++++++---------- > 1 file changed, 22 insertions(+), 10 deletions(-) Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> thanks, -- John Hubbard NVIDIA > > diff --git a/mm/gup.c b/mm/gup.c > index 8f236a3..c36c621 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -734,11 +734,17 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) > * Or NULL if the caller does not require them. > * @nonblocking: whether waiting for disk IO or mmap_sem contention > * > - * Returns number of pages pinned. This may be fewer than the number > - * requested. If nr_pages is 0 or negative, returns 0. If no pages > - * were pinned, returns -errno. Each page returned must be released > - * with a put_page() call when it is finished with. vmas will only > - * remain valid while mmap_sem is held. > + * Returns either number of pages pinned (which may be less than the > + * number requested), or an error. Details about the return value: > + * > + * -- If nr_pages is 0, returns 0. > + * -- If nr_pages is >0, but no pages were pinned, returns -errno. > + * -- If nr_pages is >0, and some pages were pinned, returns the number of > + * pages pinned. Again, this may be less than nr_pages. > + * > + * The caller is responsible for releasing returned @pages, via put_page(). > + * > + * @vmas are valid only as long as mmap_sem is held. > * > * Must be called with mmap_sem held. It may be released. See below. > * > @@ -1107,11 +1113,17 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, > * subsequently whether VM_FAULT_RETRY functionality can be > * utilised. Lock must initially be held. > * > - * Returns number of pages pinned. This may be fewer than the number > - * requested. If nr_pages is 0 or negative, returns 0. If no pages > - * were pinned, returns -errno. Each page returned must be released > - * with a put_page() call when it is finished with. vmas will only > - * remain valid while mmap_sem is held. > + * Returns either number of pages pinned (which may be less than the > + * number requested), or an error. Details about the return value: > + * > + * -- If nr_pages is 0, returns 0. > + * -- If nr_pages is >0, but no pages were pinned, returns -errno. > + * -- If nr_pages is >0, and some pages were pinned, returns the number of > + * pages pinned. Again, this may be less than nr_pages. > + * > + * The caller is responsible for releasing returned @pages, via put_page(). > + * > + * @vmas are valid only as long as mmap_sem is held. > * > * Must be called with mmap_sem held for read or write. > * >
